1. Field of the invention
This invention relates in general to grain harvesting combines, and in particular to an elevator system for transporting clean grain from the sieve section to the storage bin and tailings from the sieve section to the rotor for rethreshing.
2. Summary of the Prior Art
A grain harvesting combine has a header which cuts the crop and feeds it upward into a threshing rotor. The threshing rotor rotates within a perforated housing, threshing grain from the crop. The threshed grain falls through the perforations onto a grain pan, and from the grain pan onto a set of upper and lower sieves. The sieves are oscillating, causing clean grain to fall through for collection. A blower blows air upward through the sieves, discharging chaff to the rear. Straw from the threshing chamber proceeds through a straw beater and also out the rear.
The clean grain in the prior art type is conveyed to the bin typically by a conveyor which is a combination of horizontal augers and vertical elevators. Incompletely threshed grain will not proceed through the fingers of the sieves, yet is too heavy to be blown out the rear along with the chaff. This grain, called "tailings" or "returns" is returned to the rotor for rethreshing. Typically in the prior art, the tailings are conveyed to the rotor by a separate conveyor which is a combination of augers and elevators.